Question
Evaluate, using $(a + b)(a - b)= a^2 - b^2,4.9 \times 5.1$
✓
Answer
$4.9 \times 5.1$
$= (5 - 0.1) \times (5 + 0.1)$
$= (5)^2 - (0.1)^2$
$= 25 - 0.01$
$= 24.99.$
$= (5 - 0.1) \times (5 + 0.1)$
$= (5)^2 - (0.1)^2$
$= 25 - 0.01$
$= 24.99.$
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